Method and device for procuding a switch cylinder

ABSTRACT

To produce a switch cylinder ( 1 ) with a cam ( 2 ) extending about its periphery, with side flanks ( 3 ) projecting radially, and changing its direction in its run, a tubular piece or a deep-drawn rotational body ( 10 ) made of metal is compressed in axial direction and bulged out along the run of the cam ( 2 ) and the bulged area ( 20 ) is axially compressed by tools ( 5, 6 ) moved axially toward one another and surrounding the adjacent areas of the bulge ( 20 ) on the outside, each of the edges of which having the run of the flanks ( 3 ) of the cam ( 2 ).

BACKGROUND

The invention relates to a method for producing a switch cylinder having a cam extending about its periphery with side flanks protruding radially and changing its direction in its run.

Cams of this type extending about the periphery of a cylinder housing are known in diverse shapes and for diverse uses and are used to move a fork-shaped or groove-shaped counterpart back and forth during a rotation of the cylinder in accordance with the run of this cam or vice-versa to move the cylinder in axial direction during its rotation with a stationary fork part.

Cylinders of this type with cams are often required, for example, in gear-shift mechanisms of motor vehicles or motorcycles. The switch cylinders or control cylinders known to date are made, for example, of a solid material by cutting or by casting. However, in many cases, this means an unjustifiably high weight. Moreover, a production of this type is also very expensive.

A control cylinder produced by non-cutting, i.e. a switch cylinder, is known from DE 196 45 791 A1 which is composed of individual parts which are each made by non-cutting by a shaping process. In this case, the actual roll body is a tubular body which is brought into the desired shape by high-pressure shaping, i.e. by a hydraulic expansion, which should be considered as an expensive manufacturing process in which a corresponding outer form is required.

SUMMARY

Therefore, the object is to create a method and also a device for producing a control cylinder or switch cylinder of this type having a peripherally extending, raised cam which has as slight a weight as possible and yet exhibits high stability.

To solve this object, the method defined above for producing the switch cylinder is characterized in that a tubular piece or a deep-drawn rotational body made of metal is compressed in axial direction and bulged according to the run of the cam and that the bulged area is axially compressed by tools surrounding the adjacent areas of the bulge on the outside and moved axially together, the edges of which have the run of the flanks of the cam in each case. Thus, the bead forming due to the compression and bulging on the outside of the switch cylinder can thus extend closed on itself about the tubular piece or the hollow body, but can also in this way change the direction, if necessary, also repeatedly, and thus form a cam.

As a result of this shaping, the resultant switch cylinder is in one piece and seamless, so that a high stability is obtained at a low weight preset by the shaped rotational body.

An especially advantageous manner of proceeding with the method of the invention can lie in that a first or upper tool overlaps the tubular piece or the hollow cylinder on one end and surrounds it on the periphery up to the area to be bulged, that a second or lower tool overlaps the other end of the tubular piece or hollow body and surrounds the outer periphery on the other side of the later cam and the outer surface of the tubular piece or hollow body and that the surface area to be bulged and shaped into a cam is released by both tools, that the one tool is then moved in direction toward the other tool in axial direction of the tubular piece or hollow cylinder or both tools are moved toward one another in this direction and the tubular piece or hollow cylinder is compressed and bulged between the tools and that the bulge is enlarged proportionately to the approach of the tools in radial direction and reduced in axial direction. As a result, many different cams can be formed as one piece onto the tubular piece or hollow cylinder in a few steps and with simple means.

To make the cam as stable as possible, it is advantageous if the compressed bulge is pressed together in such a manner that the inner sides of the flanks contact one another. This makes a subsequent deformation of the cam more difficult in a practical application because the cam has almost twice the wall thickness of the hollow cylinder. In addition, a cam is produced which has essentially parallel flanks and high stability.

This increased stability of the flanks of the cam can be advantageously combined with an enlarged radial expansion of the cam if the compression of the tubular piece or hollow cylinder is carried out in at least two steps, the tubular piece or hollow cylinder first being axially shaped and compressed with a first upper and lower tool until the bulge forms and if it is then placed in a second upper and lower tool and further axially shaped and compressed, in particular until the inner sides of the flanks of the bulge of the tubular piece or hollow cylinder come into contact. By bulging the material in steps, the material can be more intensely shaped and in or to a greater degree.

When shaping the workpiece in one or at least two steps, it is advantageous if the tubular piece or hollow cylinder is supported or stabilized on the inside during shaping by a core tool. As a result, the inner side of the workpiece can remain deformationfree and smooth. In addition, the forces acting on the workpiece are better directed into the areas to be shaped.

To be able to make the cam to be shaped as dimensionally accurate as possible, it is advantageous if the shaping of the cam is radially limited with aid of a side stop. The cam comes to rest against this side stop during shaping and is thereby radially compressed. This radially limited bulge of the hollow cylinder now lets the material flow into the flanks of the bulge after the limit or side stop has been reached during further shaping and, as a result, the flanks are further stabilized. In addition, the diameter of the switch cylinder can be more accurately set during production than without a radial restriction of the bulge.

Depending on the design of the side stop, the peripheral surface of the cam be simultaneously formed. For example, it can be cylindrically shaped.

A device which is especially suitable for carrying out the method described above and to solve the object for producing a switch cylinder made of metal from a tubular piece or a deep-drawn rotational body can have at least two tools with cylindrical recesses for receiving the tubular or cylindrical workpiece which can be moved together in axial direction and compressed after the workpiece has been inserted and their edges facing one another deviate from a plane of the diameter and extend parallel to one another and are bent corresponding to a cam to be bulged or formed radially between them.

During compression, the tubular piece or hollow cylinder can be stopped thereby that the tools each have abutments for the front end of the tubular or cylindrical workpiece on the end of their cylindrical hollows facing away from the recess, the outer diameter of which correspond to the inside diameter of the cylindrical hollows. As a result, the force acting on the workpiece is exerted axially and only onto the wall, so that only the wall of the workpiece is compressed.

It is advantageous for compressing the cylindrical workpiece if the edges of the tools facing one another and extending along the cam to be formed on each have or leave blank a peripherally extending recess for receiving the radial bead to be formed during compression of the two forms. This enables a bulging and flow of the material into the desired shape.

The outward flow of the material is advantageously assisted if a cylindrical core tool is placed inside the tubular piece or hollow cylinder, the outer diameter of the core tool corresponding to the inside diameter of the tubular piece or hollow cylinder. As a result, the inside of the workpiece can remain deformation-free and the material can only be shaped outward.

Advantageously, the outward flow of the material for a good dimensional stability of the cam to be formed is limited thereby that at least one of the two tools has a radial limit or a side stop in the area of the tubular piece or hollow cylinder left blank axially by placing the edge corresponding to the cam in an indentation radially limited by said side stop. If the material reaches the side stop, it can flow away from the side stop into the flanks of the cam during further shaping. Thus, the flanks can also be placed against the upper and lower limit of the recess, which also corresponds to a higher dimensional stability.

It can thereby be advantageous if the radial limit or the side stop of the cam on the tools extends parallel to the directon of compression of the tubular piece or hollow cylinder. As a result, the material of the hollow cylinder can flow especially easily into the form preset by the tool during an axial movement of the upper and lower tool.

The switch cylinder which can be produced with the method of the invention and which has a radially projecting cam extending on its cylindrical surface consists of a tubular piece or a deepdrawn cylinder on which the cam is formed in one piece by axial compression. This construction of the switch cylinder offers a high stability against forces acting during operation with a low weight and thus a long-term accurate guide of the components acting on the cam.

For a high stability of the switch cylinder, it is advantageous if it has a bottom connected with it in one piece on one end. In addition, this bottom can offer various fastening possibilities during practical use of the switch cylinder.

In an advantageous embodiment, the bottom connected in one piece with the cylinder on one end can be centrally penetrated and can thereby be deep-drawn in axial direction in a central area and this opening can serve as a bearing position for a shaft, arbor or rod extending through the switch cylinder. As a result, the switch cylinder can perform a rotating motion about its own axis and guide the counterparts abutting the cam.

If the metal hollow cylinder is compressed with a tool having tool parts of this type, a bead is formed which extends on the outer periphery corresponding to the edges deviating from a plane and thus produces the desired cam which can thereby have preset changes in direction and various slopes.

Above all, when combining individual or several of the aforementioned steps and features, a one-piece and seamless switch cylinder results which, in addition to a low weight, can also have a high stability. With the method according to the invention, the switch cylinder can be produced in a cost effective manner and in a few steps.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments of the invention are described in greater detail in the following with reference to the drawings, showing in part in a schematic representation:

FIG. 1 a perspective representation of a switch cylinder with bottom,

FIG. 2 a perspective representation of a switch cylinder without a bottom,

FIG. 3 a longitudinal section of a starting workpiece for the production of the switch cylinder prior to the compression,

FIG. 4 a longitudinal section of the tool with a workpiece after completed compression,

FIG. 5 a representation corresponding to FIG. 4, the recess of the lower tool having a side stop,

FIG. 6 a longitudinal section of the tool with a workpiece after the first step of a two-step compression,

FIG. 7 a longitudinal section of the tool with a workpiece after the second step of a two-step compression, and

FIG. 8 a longitudinal section through a switch cylinder produced according to the method of the invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The left half of the drawing in each of FIGS. 3 to 8 shows a workpiece in the form of a tubular piece without a bottom and a workpiece in the form of a deep-drawn hollow cylinder with a bottom is illustrated in the right half of each of said drawings. In the following figures, parts that have the same function, even with a different structural design, have the same reference numbers.

FIG. 1 shows a switch cylinder 1 having a radially projecting cam 2 extending on the cylindrical surface thereof, the cam 2 being formed in one piece onto a deep-drawn hollow cylinder 10 by axial compression. The switch cylinder 1 has a bottom 4 on its upper end which is connected as one piece with the switch cylinder 1.

FIG. 2 shows a switch cylinder 1 similar to the embodiment in FIG. 1. In contrast to the one shown in FIG. 1, the switch cylinder 1 shown in this case consists of a tubular piece 10 without a bottom onto which the cam 2 is formed in one piece by axial compression.

FIG. 3 shows the two embodiments with and without bottom in cross section prior to shaping.

A device for producing a switch cylinder 1 can be seen in FIG. 4, said device having two tools 5 and 6 with cylindrical, peripherally extending recesses 8 for accommodating the tubular or cylindrical workpiece 10 which can be moved and compressed together in axial direction after the workpiece 10 has been inserted and their edges 51 and 61 facing one another which extend so as to deviate from a diameter plane and extend parallel to one another and are bent corresponding to a radial cam 2 to be bulged or formed between them. An already compressed workpiece 10 is shown between the upper tool 5 and lower tool 6, the cam 2 of which was formed in the recess 8. In this case, the flanks 3 of the cam 2 adjoin one another with their inner sides. To accommodate the workpiece 10, the tools 5 and 6 each have abutments 7 for the front end of the workpiece 10 on the end of their cylindrical hollows facing away from the recess 8, the outer diameter thereof corresponding to the inside diameter of the cylindrical hollows.

FIG. 4 shows a core tool 11, which can also be seen in FIGS. 5 and 6, situated inside the workpiece 10, the outer diameter of which corresponds to the inside diameter of the workpiece 10. As a result, the inner side of the workpiece 10 is stabilized against a deformation on the inside.

Thus, during production of the switch cylinder 1, the procedure is as follows: the tubular piece or the deep-drawn rotational body 10 made of metal is compressed in axial direction with aid of the tools 5 and 6 and bulged out along the run of the cam 2. The area 20 which is at first only slightly bulged and then bulged more and more as the tools 5 and 6 draw closer is compressed by the edges 51 and 61 of the tools 5 and 6 moved toward one another and which also surround the bulge 21 on the outside, the edges 51 and 61 each having the run of the resultant flanks 3 of the cam 2.

As per the representation in FIG. 4, FIG. 5 shows upper and lower tool 5 and 6 as well as the workpiece 10 compressed by the tools 5 and 6 moved toward one another between said tools 5 and 6. In this embodiment of the device, the lower tool 6 has a radial limit extending parallel to the direction of compression of the workpiece 10 or a side stop 9 in the recess 8 which is adjoined by the outer surface 21 of the bulge 20 forming the cam 2 in the last phase of the shaping of the cam 2. The side stop 9 is the radial limit of an indentation in which the edge 61 of the lower tool 6 extends in this case.

Since this side stop 9 has a cylindrical inner contour, a surface 21 with axially parallel surface lines also results therefrom, while the surface lines of this outer surface 21 are bent in a switch cylinder 1 which was produced in a set of tools according to FIG. 4.

FIGS. 6 and 7 show a two-step procedure for producing a switch cylinder 1 from a tubular piece with or without a bottom.

In FIG. 6, the end of the first step of the method can be seen in which the workpiece 10 found between the upper tool 5 and lower tool 6 is axially deformed and compressed by the tools 5 and 6 to be moved toward one another until the bulge 20 is formed in the recess 8. In this first step, the inner sides of the flanks 3 of the bulge 22 do not as yet come into contact. Optionally, this first procedural step could also already be the end of the compression process if the bulge is already sufficiently formed as control means for a specific application.

However, FIG. 6 could also be viewed as a representation of a single-step production of a switch cylinder 1 in which the cam 2 remains hollow, i.e. the flanks 3 are not deformed until they come into contact, but continue to be provided with a space.

In practice, a switch cylinder 1 could be produced which already has its final form in FIG. 6.

For the end of the second step of the compression shown in FIG. 7, another lower tool 6 is used than the one in the first step which now has a radial limit or a side stop 9 extending parallel to the direction of compression of the workpiece 10, corresponding to that of FIG. 5. With aid of this lower tool 6, the axial compression of the workpiece 10 is now continued until the bulge 20 forming the cam 2 has assumed the shape of the recess 8, the inner sides of the flanks 3 come into contact with the cam 2 and the outer surface 21 of the cam 2 is placed against the side stop 9.

FIG. 8 shows a switch cylinder 1 produced with the abovedescribed device and consisting of a tubular piece or a deepdrawn cylinder 10 with the cam 2 extending on its cylindrical surface, radially projecting and formed in one piece, again in cross section without the tools 5 and 6 surrounding it.

To produce a switch cylinder 1 having a cam 2 extending about its periphery with side flanks 3 radially projecting and changing its direction in its run, a tubular piece or a deep-drawn rotational body 10 consisting of metal is compressed in axial direction and bulged out along the run of the cam 2 and the bulged area 20 is axially compressed by tools 5, 6 axially moved toward one another and surrounding the adjacent areas of the bulge 20 on the outside, each of their edges 51 and 61 having the run of the flanks 3 of the cam 2. 

1. Method for the production of a switch cylinder (1) with a cam (2) extending about its periphery, with side flanks (3) projecting radially and changing its direction in its run, characterized in that a tubular piece or a deep-drawn rotational body (10) made of metal is compressed in an axial direction and bulged out in an area to be bulged along the run of the cam (2) and that the bulged area (20) is axially compressed by tools (5, 6) moved axially toward one another and surrounding adjacent areas of the bulge (20) on an outside, edges (51, 61) of the tools having the run of the flanks (3) of the cam (2).
 2. Method according to claim 1, characterized in that a first or upper tool (5) overlaps the tubular piece or body (10) at one end and surrounds it at its periphery up to the area (20) to be bulged, a second or lower tool (6) overlaps the other end of the tubular piece or body (10) and surrounds an outer periphery found on an other side of the subsequent cam (2) and the outer surface of the tubular piece or hollow body (10) and that the surface area to be bulged and formed into the cam (2) is left free by the two tools (5, 6), and the one tool (5 or 6) is then moved in a direction toward the other tool (5 or 6) in an axial direction of the tubular piece or hollow cylinder (10) or that both tools (5, 6) are moved toward one another in this direction and the tubular piece or hollow cylinder (10) is compressed and bulged out between the tools (5, 6) and the bulge (20) is proportionately enlarged to the approach of the tools (5, 6) in a radial direction and reduced in the axial direction.
 3. Method according to claim 1, characterized in that the upset bulge (20) is compressed in such a way that inner sides of the flanks (3) come into contact.
 4. Method according to claim 1, characterized in that the compression of the tubular piece or hollow cylinder (10) is performed in at least two steps, the tubular piece or hollow cylinder (10) first being axially shaped and compressed with a first upper and lower tool (5, 6) until the bulge (20) is formed and it is subsequently placed in a second upper and lower tool (5, 6) and further axially shaped and compressed, in particular until the inner sides of the flanks (3) of the bulge (20) of the tubular piece or hollow cylinder (10) come into contact.
 5. Method according to claim 1, characterized in that the tubular piece or hollow cylinder (10) is stabilized on the inside during shaping by a core tool (11).
 6. Method according to claim 1, characterized in that the shaping of the cam (2) is radially limited with a side stop (9).
 7. Method according to claim 6, characterized in that the cam (2) abuts against the side stop (9) during the axial shaping and, as a result, is radially compressed.
 8. Device for producing a switch cylinder (1) made of metal from a tubular piece or a deep-drawn rotational body, characterized in that it has at least two tools (5, 6) with cylindrical recesses (8) for accommodating a tubular or cylindrical workpiece (10), which can be moved and compressed toward one another in an axial direction after the workpiece (10) has been inserted and edges (51, 61) of the tools facing one another deviate from a plane of a diameter and extend parallel to one another and are bent to correspond to a radial cam (2) to be bulged out or formed between the tools.
 9. Device according to claim 8, characterized in that the tools (5, 6) each have abutments (7) on each end of cylindrical hollows thereof facing away from the recess (8) for the end of the tubular or cylindrical workpiece (10), an outer diameter of which corresponds to an inside diameter of the cylindrical hollow.
 10. Device according to claim 8, characterized in that the edges (51, 61) of the tools facing one another and extending according to the cam (2) to be shaped each have or leave free a peripherally extending recess (8) for accommodating a radial bead (22) to be shaped during compression of the two forms (5, 6).
 11. Device according to claim 8, characterized in that a cylindrical core tool (11) is situated inside the tubular piece or hollow cylinder (10), the outer diameter of the core tool (11) corresponding to the inside diameter of the tubular piece or hollow cylinder (10).
 12. Device according to claim 8, characterized in that at least one of the two tools (5, 6) has a radial limit or a side stop (9) in the axially area left free of the tubular piece or hollow cylinder (10).
 13. Device according to claim 8, characterized in that the radial limit or the side stop (9) of the cam (2) extends parallel to the direction of compression of the tubular piece or hollow cylinder (10) on the tools (5, 6).
 14. Switch cylinder (1) having a radially projecting cam (2) extending on its cylindrical surface, consisting of a tubular piece or a deep-drawn cylinder (10) on which the cam (2) is formed in one piece by axial compression.
 15. Switch cylinder (1) according to claim 14, characterized in that it has a bottom (4) on one end connected with it in one piece.
 16. Switch cylinder (1) according to claim 14, characterized in that the bottom (4) on one end and connected with the switch cylinder (1) in one piece is penetrated in the centre and is thereby deep-drawn in axial direction in a central area and that this opening serves as a bearing for a shaft extending through the switch cylinder (1). 